Dual-homed networking is one of the commonly used networking technologies at present, and can improve the reliability of a network through a switching between a main link and a backup link when a link fails. In a normal condition, the traffic passes through the main link, when the main link fails, the traffic is switched to the backup link for protection, so as to improve the reliability of network transmission in performance.
FIG. 1 shows a schematic diagram illustrating an Ethernet dual-homed networking mode in the prior art, a dual-homed protection domain A shown in FIG. 1 is a region configured with an Ethernet dual-homed connection protection protocol, which may be a node or a plurality of nodes. The dual-homed protection domain A provides two links upward, i.e., a main link and a backup link which access Internet in a dual-homed mode through a plurality of nodes (at least two nodes: E1 and E2). If the dual-homed protection domain A configured with the dual-homed connection protection protocol detects a failure of a link or node which is directly connected with the dual-homed protection domain A, the dual-homed protection domain A switches the traffic on the failure link to the backup link by protection switching so as to improve the robustness of the network; for example, when the main link fails, the traffic on the main link is switched to the backup link. Wherein, as shown in FIG. 1, the link between the dual-homed protection domain A and a node M1 is called a main link, the link between the dual-homed protection domain A and a node M2 is called a backup link, the dual-homed protection domain A→the node M1→the node E1→the Internet is called a path, the path in which the main link is located is called a main path, and the path in which the backup link is located is called a backup path. The small circle drawn at one end of the backup link shown in FIG. 1 indicates that in the normal condition the backup link is blocked and the traffic does not pass through the backup link.
However, when a node or link on an upper layer fails, the dual-homed protection domain A cannot perceive it; for example, when a failure occurs in the link between the M1 and the E1 or the link between the E1 and the Internet, the main path from the dual-homed protection domain A to the Internet via the M1 and the E1 is unavailable, a protection switching of the traffic should be realized as soon as possible, otherwise, loss of a large amount of data is caused and then the network performance is severely influenced. However, in the prior art, the dual-homed protection domain A cannot perceive the above condition in time, so that a fast protection switching cannot be realized.